Break in for new cams and Cam follower??

[M3NTO_M]

I know this is probably a obvious answer is break in is needed for new cams and cam followers.
I talked with Vac Motor sports and they said their is no need for break in period for new cams and followers ??

Which is true ?

I'm more on the break in period side.
what would be a good break in period for new cams and followers ?
1200mi?
2000mi?

[cobra]

not needed

[Slideways]

The stock engine had a break-in period of 1200 miles, so that is one way to go. I've also seen on a rebuild of a 964 Porsche engine where the shop owner kept the engine revving at around 2-3k RPM immediately during the first startup for a few minutes. Then they redlined it after a test drive or two.

[M3NTO_M]

I'm currently in the process of a cylinder head rebuild.

I know for other cars, you need to break it in if you have new cams and Followers.

With the rebuild it has all new valve train components.

I would assume you would potentially?

I guess not.. interesting.


Thanks !

[Mr.wReckless]

Spoke with Catcams when I fitted mine, they advised 2k RPM for 20 mins (approx.) Otherwise I've not really seen that it's definitely needed..?

Regards

[cobra]

There should be nothing to break in. It's just like doing your rod bearings.

[Pklauser]

Other cars I've done cams on have recommended doing varied rpms above 3K for 20mins, similar to stated above. Reason explained was something about keeping oil pressure up for wearing in the cam.

No idea the amount of truth to that, just what I've been told in the past.

[digger]

There should be nothing to break in. It's just like doing your rod bearings.

Totally wrong on all levels

the cam follower interface needs to be broken in as it is not hydrodynamic lubrication

lots of breakin lube run at 2-2.5k 20 min. Make sure clearances are good

[sapote]

There should be nothing to break in. It's just like doing your rod bearings.

In theory the crank journal doesn't touch the rod bearing as there is a high pressure oil film in between; the cam lobe is sliding against the follower -- metal to metal, and so their contact surfaces need to be lapped together before carrying higher load.

[Syfon]

Brand new cams/followers must be broken in. The cam & follower are always in contact. Break in is absolutely critical to establish wear patterns and longevity. Plenty of assembly lube and 2-3k rpm for ~20minutes. After that, change the oil and begin sending.

[Syfon]

The stock engine had a break-in period of 1200 miles, so that is one way to go. I've also seen on a rebuild of a 964 Porsche engine where the shop owner kept the engine revving at around 2-3k RPM immediately during the first startup for a few minutes. Then they redlined it after a test drive or two.

When the engine is brand new, everything is brand new including the driveline etc.. Therefore driving it relatively gently for the first ~2,000km is recommended.

The rebuild of said 964 engine and following run-in procedure of 2-3k rpm for 15-20 minutes is an absolute must to ensure the piston rings seat correctly against the bores.

There should be nothing to break in. It's just like doing your rod bearings.

That's incorrect. Bearings don't need breaking in as they do not and should never contact the crank due to riding on a film of pressurized oil. Cams in these engines however are always in contact with the follower (i.e. metal to metal with a very small oil film for lubrication); it is imperative to break them in correctly. Much like the process to seat piston rings. If it's not done, you'll have problems.

[cobra]

I'm not sure I follow, someone please educate me (serious)

1. If the cams and followers were metal-to-metal, they would wear out in short order. There must be an oil film preventing the metals from touching at a microscopic level. Sure it's not a pressurized journal like the crank/rods but the end result is similar.

2. What is running the engine at 2500RPM for 20 minutes going to achieve that driving the car normally won't? The valve train doesn't know if you're driving or revving with no load.

[digger]

I'm not sure I follow, someone please educate me (serious)

1. If the cams and followers were metal-to-metal, they would wear out in short order. There must be an oil film preventing the metals from touching at a microscopic level. Sure it's not a pressurized journal like the crank/rods but the end result is similar.

2. What is running the engine at 2500RPM for 20 minutes going to achieve that driving the car normally won't? The valve train doesn't know if you're driving or revving with no load.

1) google "Stribeck" curve, the conditions at cam does not generate a full film to totally separate surfaces. yes without good oil with high pressure additives it will wear out in less than 30min. this is why the internet is plastered full of ZDDP info as solid flat tappet pushrod engines are very sensitive to this, the s54 a little less so but same principle at play on anything where the cam wipes rather than rolls over follower, rocker, lifter, bucket etc

2) 2500 rpm generates more oil flow to flood and lubricate things (more oil pressure), also takes a bit of load off the nose of the cam due to inertia effects and improved oil entrainment

[cobra]

1) google "Stribeck" curve, the conditions at cam does not generate a full film to totally separate surfaces. yes without good oil with high pressure additives it will wear out in less than 30min. this is why the internet is plastered full of ZDDP info as solid flat tappet pushrod engines are very sensitive to this, the s54 a little less so but same principle at play on anything where the cam wipes rather than rolls over follower, rocker, lifter, bucket etc

2) 2500 rpm generates more oil flow to flood and lubricate things (more oil pressure), also takes a bit of load off the nose of the cam due to inertia effects and improved oil entrainment

I think if you poured a quart of oil over your cams before installing the valve cover, and drove it normally, it would work perfectly fine. No need to do anything special.

[sapote]

I think if you poured a quart of oil over your cams before installing the valve cover, and drove it normally, it would work perfectly fine. No need to do anything special.

I guess you can find this out on your engine, next time when it has new followers and cam.

With this thinking, then why the auto industry invented the word "break in"?